delay vs buy time

delay is a noun but buy time is not a noun.

Word	Noun	Adjective	Verb	Adverb
delay	Yes	No	Yes	No
buy time	No	No	Yes	No

As verbs, buy time is a hyponym of delay; that is, buy time is a word with a more specific, narrower meaning than delay:

delay: cause to be slowed down or delayed
buy time: act so as to delay an event or action in order to gain an advantage

Other hyponyms of delay include stonewall, catch, stall.

delay (noun)	buy time (noun)
the act of delaying; inactivity resulting in something being put off until a later time
time during which some action is awaited

delay (verb)	buy time (verb)
cause to be slowed down or delayed	act so as to delay an event or action in order to gain an advantage
stop or halt
slow the growth or development of
act later than planned, scheduled, or required